Fuel antiknock



p 2,794,715 7 1C patented June-'4, 1957 FUEL VANTIKNQCK John D. Bartleson, Franklin, Mieh., assignor to Ethyl Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application August -13, 1953, Serial No. 374,153

7 Claims. (Cl. 44-66) This invention relates to the-improvement of organolead material, and in'particular to adjuvants for tetraethyllead and tetraethyllead-containing compositions.

Organolead compounds such as vtetraphenyllead, tetramethyllead, tetraethyllead, dimethyldiethyllead, and .the like have long been known as antiknock agentsfor fuel for spark ignition type internal combustion engines. Of such materials, however, only tetraethyllead hasattained commercial success because of its eflicacious attributes. Likewise, it has long been known that the efiective utilization of such antiknock agents is enhanced by providing antiknock fluids which consist of organic halogen-compounds in admixture with an organolead compound.

Organolead compounds suffer one disadvantage, particularly during storage, handling, and blending operations, namely, their inherent instability. Thus, tetraethyllead and related compounds are susceptible of deterioration which is largely dependent upon the nature .of the environment. For example, it has been found that organolead antiknock agents and antiknockfluidscontaining the same, when in contact with certain metals, such as copper andcopper-containing alloys, tend to deteriorate, even in a reducing atmosphere. Such deterioration is postulated to result from an adverse catalytic activity exhibited by such metals. In other words,- it is generally believed that copper .and like metals .act as self-perpetuating decomposition accelerators. Another condition enhancing the deterioration of such antiknock agents is contact with air. It is generally believed that atmospheric constituents, notably oxygen and ozone, tend to oxidize one or more of the lead-to-carbonbonds with the formation of insoluble decomposition products. Under these conditions there contemporaneously occurs a color change in the dyestuff normally present in andknock fluids such that the visual identification of -the product frequently becomes diflicult, if not impossible. organolead antiknock agents are likewise decomposed on exposure to strong light, particularly sunlight. 'In this case the decomposition is attributed to the catalytic -decomposition of the organolead compounds by ultra-violet light. It is apparent, therefore, that the exposure of tetraethyllead and tetraethyllead-containing compositions to any or all of the above environments results in a number of operational difliculties, including loss of antiknock effectiveness, the formation of sludge and other types .of sediment, and the like.

When organolead-containing compositions areutilized in internal combustion engines, other difliculties are frequently encountered. For example, in spite of the high degree of eificiency of the normal scavenger complement in antiknock fluids, the accumulation of engine deposits in the engine cannot be entirely prevented. Such deposition is particularly prevalent when spark ignition engines are operated under conditions of low speed and light load, such as encountered in metropolitan driving conditions. As a result of notable improvements in fuel antiknock quality which have been made in recent years, such deposits present but a few minor problems in low compression engines. However, because of -the trend in the automotive industry of utilizing high compression engines in passenger cars and trucks, the accumulation of deposits results in a number of relatively serious problems, including increased detonation, deposit-induced autoignition or-wild ping, spark plug fouling, reduction-in exhaust valve life, and the like.

Of the problems previously enumerated, those of wild ping, spark plug fouling, and-reduced exhaust valve life are of considerable concern to the automotive industry. This results from the fact that each time the lead con centration in the fuel is raised to coincide with increases in compression ratio to eliminate detonation, the magnitude of one or more'of these problems generally increases. As a result, there is a paramount need existing for anew and improved method for altering the physical and chemical characteristics of deposits and for modifying the combustion process such that thewell-known detrimental effects of the previously described "deposit-induced engine phenomena can 'be markedly suppressed or be eliminated.

"It is, therefore, an object of this invention to provide adjuvants "for organolead compounds. It is likewise an object of this invention to provide means of improving compositions such as antiknock fluids and fuels which contain'organoleadantiknock agents. Similarly, the'provision of improved organolead compositions is another 'object of this invention. 'A particular object of this inventionis to provide improved tetrae'thyllead containingfuels,'especially those 'for use in "spark ignition type internal combustion engines. "In addition, an "object of this invention is to provide methods of improving antiknock fluids such that during compoundingstorage, and blending operations such materials are stabilized against the adverse elfects of deteriorative environments. An additional object of the instant invention is to provide means of obviating deposit-induced phenomena 'of'the character described hereinbefore. 'Other important objects of'this invention will be apparent'from the-discussionlhereinafter.

Itshas now been found that the above and other ob jectsiof this invention are attained by providingcompositions of matter adapted for use as additives to fuel for spark-fired internal combustion engines comprising :an organolead antiknock agent, and, in quantity su'ificient toistabilize 1'01 improve said agent, a'product'obta'inedby reaction'between a phosphorous sulfide and a compound containing at least one substituted carbon atom 'which is doubly bonded to a group VI-B element, and which compound possesses at least one hydrogen atom on the carbon atom alpha to the substituted carbon atom. 'That is to ;say, the organic reactant which contains at least one hydrogen atom on the alpha carbon atom contains at leastone of'the structures Under certain conditions the corresponding selenium and tellurium compounds can be employed in forming my organolead adjuvants. Thus in the discussion hereinafter the 'termcarbonyl refers to all such group VI-B divalent radicals.

In line with the foregoing, the adjuvants of this invention are formed by reaction between such compounds as phosphorus pentasulfide (P285), phosphorus heptasulfide (P487) or the like and an aliphatic, alicyclic, aromatic or heterocyclic organic compound which contains at least one carbon atom which is attached to a group VI-B element by means of a double'bond and, further, which compound contains at least one hydrogen atom ion the carbon atom alpha to thisgroup VI-B .substitutedcarbon atom. It will thus be apparent to those skilledin the .art that the formation of my organolead adjuvants apparently involves the formation of hydrogen sulfide during the course of the reaction, which formation is facilitated by the fact that at least one hydrogen atom of my organic reactant is activated by its close proximity to a radical which may be represented as wherein A is a group VI-B element. 7 Consequently, the organic reactant used to form my adjuvants contains the characteristic moiety I II E A wherein A is a group VI-B element. For the sake of conciseness such active hydrogen-containing compounds are termed hereinafter as the organic reactants. It will be appreciated that many compounds possess the requisite chemical structure to be utilized in preparing my orgauolead adjuvants. For example, recourse can be made to organic acids, aldehydes, ketones, esters, ,B-diketones, S-ketoesters, and likewise the corresponding sulfur analogues of such materials. Consequently, so long .as the prime organic reactant used to form my adjuvants possesses the requisite activated hydrogen atom it can be successfully utilized in preparing my effective adjuvants. Inasmuch as the prime organic reactants used to form my adjuvants are well-known to those skilled in the art mention will be made of but a few for illustrative purposes. In the case of the organic acids, recourse can be made to such acids as caproic, oenanthic, caprylic, pelargonic, capric, undecylic, lauric, tridecylic, myristic, pentadecylic, palrnitic, margaric, stearic, nonadecylic, arachidic, eicosanecarboxylic, behenic lignoceric, cerotic, ,melissic, psylla'stearic, and the like. Likewise, the corresponding unsaturated acids such as erucic, oleic, citronellic, undecylenic, elaidic, ricinoleic, brassidic, nervonic, geranic, ,linoleic, aand e-elaeostearic, linolenic, dehydrogeranic, stearolic, and like acids can be used. Other acids include suberic, azeloic, sebacic, nonane-dicarboxylic, decane-dic arboxylic, undecanedicarboxylic, eicosane-dicarboxylic, phloionic, and the like. Likewise, various naphthenic acids and rosin acids can be employed in forming my organolead adjuvants. Abietic acid serves as an illustrative example of a suitable rosin acid. As indicated hereinbefore corresponding thio acids can be used. Many such substances are readily available as articles of commerce and in the cases where this is not true the methods for the preparation of such materials are well-known to the art.

Aldehydes can be used in preparing my adjuvants. It is apparent, therefore, that the aldehydes corresponding to many-of the above-described acids are capable of existence and thus can be so used. Acetaaldehyde, propionaldehyde, thio-n-butyraldehyde, isobutyraldehyde, the various thio valeraldehydes, capronaldehydes, heptaldehydes, thio acetaldehyde, cinnamic aldehyde, and the like typify the aldehydes'and thio aldehydes which can be used to prepare my adjuvants.

When utilizing ketones or thio ketones to prepare my adjuvants a wide variety of materials is available. Illustrative examples include acetone, methylethyl ketone, diethyl ketone, n-propyl ketone, methylisopropyl ketone, ethyl-n-propyl ketone, ethylisopropyl ketone, dibutyl ketone, -methylisobutyl ketone, methyl-t-butyl ketone, and analogous sulfur-containing derivatives; that is, the thio ketones, all of which contain at least one active hydrogen; Esters can likewise be employed. Therefore, upon esterifying the organic acids of the type described hereinbefore with suitable alcohols typical esters for use in ultimately accomplishing the objectives of this invention are formed. It will be appreciated, therefore, that monoand polybasic' acids and thioacids can be reacted with any'o'f the monohydric or polyhydric alcohols undersuitable conditions to provide suitable esters.

Illustrative examples of such materials include ethyl formate, methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, methyl propionate, hexyl propionate, cetyl palmitate, Degras or wool fat, octyl naphthenate, glyceryl abietate, cyclohexyl capronate, benzyl oleate, polyacrylates, polymethacrylates, polyadipates and similar substances.

Beta-diketones which can be used in preparing my adjuvants are exemplified by acetylacetone, propionyl acetone and other members of this homologous series including the corresponding fl-dithioketones. Materials closely akin to such 13-diketones are the ,B-ketoesters which are exemplified by the acetoacetic esters such as methylacetoacetate, ethylacetoacetate, propylacetoacetate, isopropylacetoacetate, butylacetoacetate, including the several positional isomers of the butyl radical, octyl acetoacetate and the like.

Restating the nature of the organic reactant used in the preparation of my organolead adjuvants, it is sufficient to indicate that so long as the compound contains at least one carbonyl or related functional group alpha to a carbon atom which contains at least one hydrogen, it can be successfully utilized. Generally speaking, beneficial results are obtained with such materials which contain up to about carbon atoms or higher in the molecule. The precise molecular weight of my organic reactants is, of course, contingent upon the nature of the substances employed and, likewise, the character of the otherprime reactant used in forming my adjuvants, namely the phosphorus sulfide.

While the organic reactants described hereinbefore for the most part represent single chemical entities, it is fre- "quently preferred to utilize'as the reactant mixtures of the various materials, especially mixtures which are readily available as articles of commerce. the presence of relatively minor quantities of materials which do not possess the chemical structure required for my organic reactants is not harmful. Indeed, in some instances these materials act as diluents for the reaction and, further, can be left in contact with my reaction products thereby acting as solubilizing agents and the like. It will be appreciated by one skilled in the art that suitable mixtures of the character described hereinbefore are obtained from various stages of petroleum refining, fats or fatty acids, byproducts from the manufacture of paper, wool and coal tar products and the like. Naphthenic acids and tall oil serve as examples.

The phosphorus sulfide, the other prime reactant utilized in the preparation of my adjuvants is preferably a reactive compound such as P255 (P4S10) and P487. It is possible, however, to use certain of the other reported phosphorus sulfides under the proper reaction conditions. Furthermore, another related reagent which can be successfully utilized in preparing my reaction products is thiophosphoryl chloride, PSC13. It will likewise be apparent that under suitable conditions the various sulfides or arsenic or antimony can be similarly employed in forming organolead adjuvants for use in the present invention.

The adjuvants of this invention are readily prepared, the reaction generally requiring only the addition of a reactive phosphorus sulfide to the organic reactant and heatiugthe mixture at a temperature at which the reac tion takes place as evidenced by the release of hydrogen sulfide until the reaction is substantially complete. The temperature of the reaction is largely dependent upon the nature of the individual reactants although, generally speaking, temperatures in the order of about 100 to about 500" F. are satisfactory. In preparing some of the adjuvants of my invention advantages are to be obtained by conducting the reaction under super-atmospheric pressure which can be readily obtained by conducting the reaction in a closed vessel thereby taking advantage of the pressure resulting from the hydrogen sulfideyso formed.

The nature of the reaction products forming the organe- In this regard,

lead adjuvants of this invention is contingent to a considerable degree upon the ratioof the reactants. Thati's to say, variations in the character of my adjuvants are achieved by utilizing dififerent organic reactant-to-phosphorus sulfide molar ratios from between about 0.5 to 1 to about to 1. v

The reaction products, that is, the adjuvants of this invention, can be made in the presence of a diluent, if desired, which may or may not be subsequently removed. Such diluents are illustrated by such substances as kerosene, straight-run and catalytically cracked hydrocarbons of the diesel fuel boiling range and the like.

The reaction products used as organolead adjuvants in accordance with this invention defy precise chemical definition. For example, although it is believed that the reaction products contain a substantial proportion of material containing PhOSPhOI'llS-lIO-rSlllfUI linkages, the true nature of the reaction and indeed the products formed is obscured by a number of competing factors. On the one hand, the ratio of the reactants determines to some extent the character of my adjuvants .as indicated hereinbefore. Furthermore, it is not inconceivable that the temperature at which the reaction is conducted will influence the amount and character of chemical cleavage, which is undoubtedly inherent in such reactions. Likewise, it will be apparent that the specific phosphorus sulfide employed will also have considerable bearing upon the nature of my adjuvants. Nevertheless, there is considerable evidence attesting to the fact that the active hydrogen present in my organic reactants is coupled with sulfur atoms from the phosphorus sulfides such that there is a release of hydrogen sulfide and the provision of acomplex molecular reaction mass. Summing .up this point, therefore, it is in praesenti impossible to adequately define the nature of my organolead adjuvants because of the fact that the reaction mechanism is highly obscured by such factors as the operation of the law of mass action, reaction kinetics, stearic factors as well consideration of the nature of the prime reactants employed. It may well be that with certain pure starting materials and with carefully controlled reaction conditions and concentrations substantially pure reaction products are obtainable. However, an advantage inherent in this invention is the fact that it is not necessary to prepare substantially pure materials and, further, that it is generally preferred to utilize the reaction product in toto as an organolead adjuvant.

The organolead antiknock agent utilized in the compositions of matter of the present invention consists of an organolead compound in which lead is directly bonded to carbon atoms. Such compounds are exemplified by the lead aryls such as tetraphenyllead, and the lead alkyl-s such as tetramethyllead, tetraethyllead, tetrapropyllead, tetrabutyllead, dimethyldiethyllead, methyltriethyllead, and the like, as well as mixtures of such compounds. Because of the generally superior characteristics of tetraethyllead and the ready accessibility thereof as an article of commerce, it constitutes a preferred embodiment of the organolead antiknock agent utilized in accordance with the instant invention.

With the various compositions within the scope of this invention the proportion of the reaction product utilized in conjunction with an organolead compound is such that there is a total of from between about 0.01 to about 0.80 theory of phosphorus. In this regard a theory of phosphorus is defined as the amount of phosphorus theoretically required to react with the lead to form lead ortho phosphate, which quantity is two atoms of phosphorus per three atoms of lead. However, generally speaking, it is sufficient to employ an organolead adjuvant of this invention such that there is an amount of phosphorus between about 0.05 and about 0.5 theory with the best overall results usually being obtained with amounts of about 0.1 to about 0.2 theory of phosphorus, the lastmentioned concentrations :constituting a preferred embodiment. 1

Regarding many of the problems frequently associated with high-octane quality fuel, an anomalous situation obtains. On one hand, an effective .adjuvant for organolead compounds should possess stability against deterioration in common environments, compatibility with the chemical entities with which it comes in contact, :and colatility so as to possess the characteristic frequently referred to as engine 'inductibility. On the other hand, the mere selection of a phosphorus compound to acquire the optimum characteristics enumerated above .doesnot necessarily assure the effectiveness of the compound in combatting such phenomena as spark plug fouling, wild ping, and the like. It is entirely probable that some empirical relationship between physical properties and effectiveness in the obviation of such problems exists, but as yet the state of the art does not contain a satisfactory relationship of this type. However, the phosphorus materials within the purview of this invention, for the most part, possess the requisite physical properties adapting them for use as organolead adjuvants and at the .same time are efiective in obviating engine problems of the type described hereinbefore.

It willbe apparent that there exists a number of variations in employing the adjuvants of thisinvention. For example,-a facet ,of this invention involves the provision of a mixture of an'organolead antiknock agent such .as a lead alkyl and a reaction product betweenphosphorus sulfide and a hydrogen, carbonyl-containing compound of the type described above. In .such a case, the resulting composition can be blended with'hydrocarbon fuel of the gasoline boiling range to provide an improved fuel composition which under certain circumstances does not require the utilization of organic halogen-containing material as a scavenger. It is believed that under these conditions the presence of a quantity of phosphorus and sulfur as above described and chemically bonded in accordance with the requirements of the reaction products used as adjuvants in this invention contributes suflicient scavenging action such that the amount and character of deposition in the engine are suitably controlled, not- Withstanding'the fact that lead phosphates generally have high melting points. Likewise, in this embodiment of the instant invention the general storage characteristics of organolead compounds are frequently enhanced.

Of perhaps more practical importance is a second variant of this invention, namely the utilization of the aforesaid reaction product between a phosphorus sulfide and an active hydrogen, carbonyl-containing compound in organolead-containing antiknock fluids. It is well known in the art thatthe most convenient means of marketing and blending organolead antiknock agents is in the form of an antiknock fluid which usually contains, in addition to the lead compound, one or more organic bromine and/ or chlorine compounds and an organic dye for identification purposes. On occasion such antiknock fluids likewise may contain minor proportions of diluents, antioxidants, metal deactivators and the like. In line with-the foregoing, therefore, a preferred embodiment of this invention involves providing improved antiknock fluids containing the requisite concentration of the above-described reaction products used as adjuvants in this invention. Such improved antiknock fluids generally do not require the presence of a solubilizing agent or a stabilizer since the phosphorus compound itself is generally'sufficiently miscible with the constituents of the antiknock fluid and imparts thereto a degree of stabilization. However, under some conditions additional benefits are to be derived by employing in the improved antiknock fluids of this invention the necessary quantities of such materials.

Still another variant of the present invention consists of providing improved fuel compositions. These normally consist of hydrocarbons of the gasoline boiling range containing a minor proportion of the aforesaid antiknock fluids of the present invention. It will be appreciated that the quantity of the antiknock fluid of the present invention utilized in my improved fuel'compositions is primarily contingent upon the use for which the gasoline'is intended. That is to say, when the fuel is intended for use in automotive engines such as passenger cars, trucks, buses and the like, an amount of any of my improved antiknock fluids equivalent to a lead content in the gasoline of from between about 0.53 and about 3.17 grams of lead per gallon is satisfactory. Thus, in the embodiments of this invention wherein I employ tetraethyllead as an antiknock agent such concentrations are equivalent to from between about 0.5 and about 3 milliliters of the compound per gallon. With the advent of the more recent high compression ratio internal combustion engines, however, it is becoming increasingly apparent that benefits are to be derived by employing somewhat greater concentrations of the organolead material in automotive gasoline. On this basis, therefore, automotive fuels containing up to about 4.75 grams of lead per gallon are contemplated. In contrast, when the improved antiknock'fluids of the present invention are utilized in fuel for aviation engines somewhat higher concentrations are employed. Generally speaking, amounts of lead up to about 6.34 grams of lead per gallon can be utilized although somewhat lesser quantities are presently in vogue. In other words, in the tetraethyllead-containing embodiments of this invention there can be present up to about 6 milliliters of tetraethyllead per gallon as an im proved antiknock fluid of my invention. Concentrations above these limits can be employed in both motor and aviation fuels, practical considerations being the prime criterion for establishing the upper concentration limit. -As indicated hereinabove, in all of the compositions of the present invention the amount of phosphorus is fixed within the limits above described. Thus, in the preferred fuel embodiments of my invention there is present :an amount of phosphorus as a reaction product between a phosphorus sulfide and an active hydrogen, carbonylcontaining compound such. that there is from about 0.1 to 0.2 theory of phosphorus. In preparing the improved fuel compositions of this invention, it is usually necessary only to add the requisite quantity of the improved fluid to the fuel and by means of stirring, shaking or other means of physical agitation homogeneous fuel compositions are provided. Although the simplest means of preparing such fuels is to blend therewith the necessary quantity of an improved antiknock fluid of this invention, it is possible to add a conventional antiknock fluid to the fuel and subsequently blend therewith the necessary quantity of my reaction product. In addition to reversing this order of addition of conventional antiknock fluids :and organic reactant-phosphorus sulfide material, another variant within the purview of this invention is to blend with the fuel each of the individual constituents of my antiknock fluids separately.

The following specific examples wherein all parts and percentages are by weight are illustrative of the methods which can be employed in preparing the organolead adjuvants of this invention.

Example I To a suitable glass reaction vessel equipped with an electric heating mantle and a stirrer is added 80 parts of wool fat and 300 parts of kerosene. To this mixture is then added 20 parts of phosphorus pentasulfide (PzSs). The temperature of the vessel is then raised to 325 F. and maintained at this temperature for a period of about 2 hours while vigorously agitating the reactants. Upon completion of the reaction the product is subjected to centrifugation and filtration so as to remove the minor quantities of undesirable products which are formed.

. Example II In a suitable reaction vessel are placedlS parts of P 85, 82 parts of tall oil and 100 parts virgin gas. oil. The temperature of the reactants is then raised to about 300? F. for a period of about 3 hours while'continuously agitating the reactants. At the end of this time the evolution of gas has substantially ceased and althougha relatively clear reaction product is formedit is preferable to resort to further purification consisting of centrifugation and filtration.

7 The reactants and reaction conditions described in the previous specific examples are merely illustrative. For example, byutilizing the above and similar reaction conditions it is possible to prepare suitable adjuvants of this invention by reacting a phosphorus sulfide such as P285, P457 and the like with such organic reactants as acetophenone, diamyl ketone, amyl acetate, methylbutyl thioketone, methyl oleate, thioacetone, and the like. Furthermore, as indicated previously it is possible to utilize thio phosphoryl chloride in forming the adjuvants of this invention. When this is done and a low organic reactantto-thiophosphoryl chloride molar ratio is employed bydrolytic treatment with hydrogen sulfide should follow the thermal step. Generally speaking, such low ratios are in the order of from about 1 to l to 2 to 1, although minor deviations from these ratios can be utilized. When a high organic reactant-to-thiophosphoryl chloride molar ratio is employed such hydrolytic treatment is generally unnecessary. In such a case, however, it is frequently desirable to conduct the reaction in the presence of a hydrogen chloride acceptor such as amines, pyridines, and the like.

To illustrate the effectiveness of the improved antiknock fluids of the present invention, consideration can be given to the problem of spark plug fouling. In order to do this, recourse can be made to the following general test procedure utilizing a standard modern V-8 engine equipped with overhead valves having a 3%" bore, a 37 stroke, a 303.7 cubic inch displacement and a com pression ratio of 7.25 to one equipped with commercially available spark plugs. In order to establish a base line this engine is operated in conjunction with an engine dynamometer on a standard commercial fuel containing 3 milliliters of tetraethyllead per gallon as conventional antiknock fluid containing 0.5 theory of bromine as ethylene dibrornide and 1.0 theory of chlorine as ethylene dichloride. The engine is operated under adurability schedule used for spark plug deposit accumulation patterned after road conditions experienced in city driving which are known to produce spark plug fouling of the greatest magnitude. Such operation is substantially continuous until a number of spark plug failures is detected thereby establishing a quantitative measure of the degree of spark plug fouling which can be expressed in average hours to plug failure. The engine is then freed from deposits and equipped with new spark plugs. The same procedure is repeated using the same fuel base stock to which is added an improved antiknock fluid of the present invention.

By way of example, when 300 gallons of a petroleum hydrocarbon fuel available as an article of commerce is treated with 900 milliliters of tetraethyllead in a fluid containing tetraethyllead, 0.5 theory of bromine as ethylene dibromide and 1.0 theory of chlorine as ethylene dichloride, a suitable fuel is prepared for establishing a base line of hours to spark plug failure. When the standard V-8 engine described hereinbefore is then operated on this homogeneous fuel composition it is found that in an average time of about 34 hours 3 sparkplug failures have occurred. a a

In contrast, when a suitable quantity of the same fuel base stock is treated with an improved antiknock fluid of the present invention greatly enhanced spark plug life is obtained. For example, when 1000 gallons of the same fuel base stock is treated with 3 liters of tetraethyllead as a fluid comprising 0.5 theory of bromine as ethylene dibromide, 1.0 theory of chlorine as ethylene dichloride, and 0.2 theory of phosphorus as the reaction product between P285 and Degras (wool fat), an improved fuel of the wild ping.

assists present invention results. Upon intimately the afofementioned components the homogeneous fuel composition containing 3.0 milliliters of tetraethyllead per gallon is suitable for use in the above-described engine test procedure. It is found that a substantial improvement in spark plug performance as evidenced by the greater period of continuous engine operation results from the utilization of such an improved fuel of the present invention. That is to say, the average hours to three spark plug failures is substantially in excess of the base line fi'gu're' of 34 hours;

When such adjuvants as those formed by the interaction of a phosphorus sulfide with tall oil, diisobutyl ketone and the like are utilized in accordance with the present in vention comparable effectiveness regarding minimization of'spark plug fouling is obtained. Without desiring to be bound by the following explanation regarding the enhanced effectiveness of the adjuva'nts of this invention a tenable explanation apparently involves a proper balance between physical properties such as stability, volatility, solubility-,conipatibility and the like and the energy relationships or ease of decomposition which may attribute to the overall effectiveness of my adjuvants by facilitating decomposition at the proper instant in the engine cycle.

To still further illustrate the enhanced elfectiveness of the organolead-containing compositions of the present invention consideration can be given to the problem of To demonstrate the effectiveness of my compositions in this regard, I can subject both a hydrocarbon fuel treated in accordance with this invention and another portion of the same hydrocarbon fuel treated with a conventional antiknock mixture to a test procedure involving the use of a single-cylinder CPR knock test engine equipped with an L-head cylinder and a wild ping counter which records the total number of wild pings which have occurred during the test periods. Such apparatus includes an extra spark plug used as an ionization gap which is installed in asecond opening in the combustion chamber. A mechanical breaker switch driven at camshaft speed is also'provided which, when closed, makes the wild ping counter ineffective for the duration of the normal flame in the combustion chamber. The breaker is open for 80 crankshaft degrees between 70 BTC (before top dead center) and ATC (after top dead center). If a flame front induced early in the cycle by deposits reaches the ionization gap during this open period, the counter registers a wild ping regardless of the-audible manifestations. During normal combustion with ignition timing at T-DC (top dead center) the flame front reaches the ionization gap at 'to 18 ATC during the period wherein the points are closed and no count is made. The actual test procedure consists essentially of operating the test engine initially having a clean combustion chamber under relatively mild cycling conditions for deposit formation until an equilibrium with regard to deposit-induced autoignition is reached. The effect of fuel treated in accordance with the instant invention is determined by comparing the test results obtained using the fuel treated with a reaction product used as an adjuvant in this invention with those obtained using a fuel treated with a conventional antiknock mixture. Since the wild ping counter records the total number of wild pings which occurred during the test procedures a quantitative expression for the amount of deposit-induced autoignition is the'number of wild pings per hour of operation. The effectiveness of my improved fuel composition in virtually eliminating deposit-induced autoignition will be apparent from the following specific examples.

Example 111 To 100 gallons of a commercially available blend of straight-run, catalytically cracked and polymer blending stocks was added and thoroughly mixed 300 milliliters of tetraethyllead as 'an antiknock fluid comprising tetraethyllead, 0.5 theory of bromine as ethylene dibromide,

and 1.0 theory'of chlorine as ethylene dichloride. The resulting homogeneous fuel composition wasthen utilized as the fuel in the previously designated singlecylinder laboratory test engine toformulate a baseline of wild ping. It was found that there were wild pings per hour of engine operation.

Example IV An improved antiknock fluid composition of the present invention is prepared by adding 0.1 theory of phos phorus as the product obtained by reaction between P285 and tall oil to milliliters of tetra-ethyllead as an antiknock fluid comprising tetraethyllead, 0.5 theory of bromine as ethylene dibrom'ide, and 1.0 theory of chlorine as ethylene dichloride. A homogeneous fluid composition is obtained by intimately mixing the aforementioned components. The entire quantity of improved antiknock fluid composition so prepared is added to 50 gallons of a commercially available blend of straight-run, catalytically cracked and polymer blending stock-s. Upon mechanically agitating the resulting mixture a homogeneous fuel composition is prepared. The laboratory single-cylinder test engine as described previously is then operated on this improved fuel composition while contemporaneously determining the rate of wild pings as detected by the wild ping counter. It is found that the utilization of an improved antiknock fuel of the present invention greatly minimizes the rate of wild pings-expressed in wild pings .per hour as contrasted with a conventional fuel which produces 135 wild pings per hour. Consequently, an improved fuel composition of this invention results in a substantial reduction in this deposit-induced engine phenomenon.

The foregoing specific examples are merely illustrative of the b'.=.-neficial eifec'ts produced by the improved organolead-containing compositions of the present invention. It will be apparent that it ispreferred to utilize the adjuvants of this invention such as the reaction products of a phosphorus sulfide and such materials as polyacrylates, coconut oil, fatty acids, methylheptyl ketone, methyl oleate, rosinacids, methyl abietate and the like in high octane quality fuel because of the .fact that most of the deposit-induced problems exist on combustion of such fuels.

The superior efie'ctiveness of the preferred embodiments of this invention, namelya reaction product between a phosphorus sulfide and an active hydrogen, carbonyl-containing compound in :the diminution of depositinduced engine problems is further unexpected when considering the prime constituents phosphorus and sulfur which are contained therein. On the one hand, both sulfur and phosphorus compounds have heretofore been judiciously avoided as much as possible in .fuel because of their notorious deleterious effects particularly .in the realm of organolead antagonismand the like. .In the case of sulfur, for example, refiners have long been resorting to various means of removing sulfur compounds from hydrocarbons of "the gasoline boiling range ;be cause of their recognized deleterious effects on .antiknock activity, engine cleanliness, storage stability, and the like. However,'the adjuvants of thisinventionpossessing considerable proportions of phosphorus 'and sulfor do not bring about such deleterious effects. Furthermore, another surprising effect has been noted, namely the fact that the presence of phosphorus-.to-sulfur bonds produces a greater effectiveness :regarding wild ping than that exhibited by compounds possessingeither phosphorus or sulfur and likewise a mixture of phosphorusand sulfur-containing compounds. This fact is evidenced by the findings that the presence of added sulfur in a conventional leaded fuel not only has no beneficial effect on wild ping but actually results in an increase in this phenomenon. By way of example, it was found'thatthe addition of 5 theories of sulfur as a mixture consisting of one-theory ofdi-t-butyl disulfide,

11 2 theories of dibutyl sulfide and 2 theories of thiophene, a mixture representative of the average sulfur constituents of petroleum hydrocarbon fuel, to a conventional gasoline containing 3 milliliters of tetraethyllead per gallon resulted in a wild ping rate of 93 wild pings per hour. In contrast, the same base fuel containing the same concentration of tetraethyllead produced 74 wild pings per hour. Thus, the incorporation of sulfur-containing compounds different from the sulfur-containing adjuvants utilized in this invention resulted in a wild ping rate amounting to 125 percent of the base line. That is to say, the presence ofssulfur-containing compounds generally increases the rate of wild ping Whereas the presence of a considerable amount of sulfur when suitably bonded in accordance with the present invention results in a definite improvement in this depositinduced phenomenon. In view of the foregoing, therefore, the apparent conclusion to be reached is that the chemical bonds between the two prime elements making up my adjuvants in some currently unexplainable manner produce enhanced effectiveness with regard to deposit-induced engine phenomena without resulting in secondary deleterious problems normally attributed to the presence of each of the elements when used separately or as mixtures of individual phosphorusand sulfur-containing compounds.

As indicated, an additional important advantage obtained from practicing this invention is the fact that my adjuvants have little or no antagonistic effect upon the antiknock agent used in the fuel. In line with the enhanced effectiveness of my organolead adjuvants this surprising benefit regarding a minimum of organolead destructiveness is perhaps associated with the degree of oxidative stability inherent in my reaction products. In other words, it is not inconceivable that my organolead adjuvants are capable of decomposing at the proper instant in the engine cycle so as to exhibit the beneficial effect regarding deposit-induced engine problems while at the same time decomposing at a time during the engine cycle sufiiciently far removed from the point at which the organolead compound exerts its beneficial antiknock activity.

Because of their adaptability the adjuvants of the present invention can be successfully utilized with any of the well known organolead antiknock agents as indicated hereinbefore. Likewise, insofar as the halide scavengers are concerned, the reaction products used as adjuvants in this invention can be employed in antiknock fluids and fuels containing such materials as ethylene dibromide, ethylene dichloride, mixed dibromotoluenes, trichlorobenzenes, and in general such organic halide scavengers as those disclosed in U. S. 1,592,954; 1,663,022; 2,364,921; 2,398,281; 2,479,900; 2,479,901; 2,479,902; 2,479,903; and 2,496,983. 'Likewi-se,the adjuvants of this invention can be used in conjunction with other well known motor fuel adjuvants' such as antioxidants, organolead stabilizers, organic dyes, solubilizers, and indeed with other catalytically active materials frequently employed in fuel.

Having fully described the nature of the present invention, the need therefor, and the best mode devised for carrying it out, it is not intended that this invention be limited except Within the spirit and scope of the appended claims. e

I claim:

1. An antiknock additive for use in hydrocarbon fuels of the gasoline boiling range, said additive comprising an organolead-antiknock agent and a product obtained by reaction between (1) a phosphorus sulfide selected from the group consisting of P 35 and P437 and (2) an organic compound containing at least one substituted carbon atom which is doubly bonded to a group VI-B element seiected from the group consisting of oxygen and sulfur and whichcompound possesses at least one hydrogen atom on the carbon atom alpha to the substituted carbon atom, said compound being further characterized by containing up to carbon atoms and by containing only elements selected from the group con sisting of carbon, hydrogen, oxygen, and sulfur, said reaction comprising heating from about 0.2 to about 10 moles of said compound per mole of said sulfide to a temperature at which hydrogen sulfide is released; said product being present in said additive in amount such that the phosphorus-to-lead atom ratio is from about 0.02/3 to about 1.6/3.

2. The additive of claim 1 further characterized in that the antiknock agent is a lead alkyl.

3. The additive of claim 1 further characterized in 7 that the antiknock agent is tetraethyllead.

4. An antiknock additive for use in hydrocarbon fuels of the gasoline boiling range said additive consisting essentially of tetraethyllead, a scavenging amount of organic halide material capable of reacting with the lead during combustion in a spark ignition internal combustion engine to form volatile lead halide, said material containing only elements selected from the group' consisting of bromine, chlorine, carbon, hydrogen, and oxygen; and a product obtained by reaction between (1) a phosphorus sulfide selected from the group consisting of P285 and P487 and (2) an organic compound containing at least one substituted carbon atom which is doubly bonded to a group VI-B element selected from the group consisting of oxygen and sulfur and which compound possesses at least one hydrogen atom on the carbon atom alpha to the substituted carbon atom, said compound being further characterized by containing up to 100 carbon atoms and by containing only elements selected from the group consisting of carbon, hydrogen, oxygen, and sulfur, said reaction comprising heating from about 0.2 to about 10 moles of said compound per mole of said sulfide to a temperature at which hydrogen sulfide is released; said product being present in said additive in amount such that the phosphorus-tolead atom ratio is from about 0.02/3 to about 1.6/3.

5. The additive of claim 4 further characterized in that said scavenging amount of organic halide material is about 0.5 theory of bromine as a bromohydrocarbon compound capable of reacting with the lead during combustion in a spark ignition internal combustion engine to form volatile lead bromide and about 1.0 theory of chlorine as a chlorohydrocarbon compound capable of reacting with the lead during combustion in a spark ignition internal combustion engine to form volatile lead chloride.

6. Hydrocarbon fuel of the gasoline boiling range adapted for use as fuel for spark ignition internal combustion engines containing up to about 6.34 grams of lead per gallon as an organolead antiknock agent, and a product obtained by reaction between (1) a phosphorus sulfide selected from the group consisting of P285 and P487 and (2) an organic compound containing at least one substituted carbon atom which is doubly bonded to a group VI-B element selected from the group consisting of oxygen and sulfur and which compound possesses at least one hydrogen atom on the carbon atom alpha to the substituted carbon atom, said compound being further characterized by containing up to 100 carbon atoms and by containing only elements selected from the group consisting of carbon, hydrogen, oxygen, and sulfur, said reaction comprising heating from about 0.2 to about 10 moles of said compound per mole of said sulfide to a temperature at which hydrogen sulfide is released; said product being present in said fuel in amount such that the phosphorus-to-lead atom ratio is from about 0.02/3 to about 1.6/3.

, 7. The hydrocarbon fuel composition of claim 6 further characterized in that itcontains from about.0.53 to about 4.75 grams of lead per gallon as tetraethyllead, about 0.5 theory of bromine as a bromohydrocarbon compound capable of reacting with the lead during combustion in a spark ignition internal combustion engine to form volatile lead bromide, and about 1.0 theory of References Cited in the file of this patent UNITED STATES PATENTS 2,378,793 Rudel June 19, 1945 14 Bartholomew Apr. 9, 1946 Campbell Aug. 13, 1946 Musselman Apr. 20, 1948 Musselman Apr. 20, 1948 Bartleson Dec. 19, 1950 Wagner July 21, 1953 Hill et a1 Ju1y'5, 1955 FOREIGN PATENTS Great Britain Nov. 26, 1952' 

6. HYDROCARBON FUEL OF THE GASOLINE BOILING RANGE ADAPTED FOR USE AS FUEL FOR SPARK IGNITION INTERNAL COMBUSTION ENGINES CONTAINING UP TO ABOUT 6.34 GRAMS OF LEAD PER GALLON AS AN ORGANOLEAD ANTIKNOCK AGENT, AND A PRODUCT OBTAINED BY REACTION BETWEEN (1) A PHOSPHORUS SULFIDE SELECTED FROM THE GROUP CONSISTING OF P2S5 AND P4S7 AND (2) AN ORGANIC COMPOUND CONTAINING AT LEAST ONE SUBSTITUTED CARBON ATOM WHICH IS DOUBLY BONDED TO A GROUP VI-B ELEMENT SELECTED FROM THE GROUP CONSISTING OF OXYGEN AND SULFUR AND WHICH COMPOUND POSSESSES AT LEAST ONE HYDROGEN ATOM ON THE CARBON ATOM ALPHA TO THE SUBSTITUTED CARBON ATOM, SAID COMPOUND BEING FURTHER CHARACTERIZED BY CONTAINING UP TO 100 CARBON ATOMS AND BY CONTAINING ONLY ELEMENTS SELECTED FROM THE GROUP CONSISTING OF CARBON, HYDROGEN, OXYGEN, AND SULFUR, SAID REACTION COMPRISING HEATING FROM ABOUT 0.2 TO ABOUT 10 MOLES OF SAID COMPOUND PER MOLE OF SAID SULFIDE TO A TEMPERATURE AT WHICH HYDROGEN SULFIDE IS RELEASED; SAID PRODUCT BEING PRESENT IN SAID FUEL IN AMOUNT SUCH THAT THE PHOSPHORUS-TO-LEAD ATOM RATIO IS FROM ABOUT 0.02/3 TO ABOUT 1.6/3. 